The present invention relates to a stent for an endoscope.
When a biliary stricture occurs, a biliary duct is narrowed to cause a clogging in a biliary duct. In such case, the flow of a bile is prevented, which may cause an icterus.
A stent is used to treat a stricture including the above mentioned biliary stricture. The stent is carried by an endoscope and inserted into a narrow portion of the annular organ (such as a biliary duct), thereby to widen the narrow portion. The stent is left in the narrow portion of the annular organ.
A conventional stent includes an expandable tube (for example, a mesh tube made of steel wires). When the stent is inserted into the annular organ, the expandable tube expands thereby to widen the narrow portion of the annular organ.
However, such conventional stent has a disadvantage such that, once the stent is left in the annular organ, it is difficult to remove the stent from the annular organ.
Further, a recently developed stent has projections which engage a surface of the annular organ, so as to prevent the stent from slipping out of the annular organ. It is further difficult to remove such stent from the annular organ.
In some cases, it is necessary to replace the stent with new one (particularly when the stent is clogged). Thus, there is strong demand of a stent which can be easily removed from an annular organ.